(a) Field of the Invention
The present invention relates to an active control type of vibration absorbing device.
(b) Description of the Related Art
In generation, vibration causes various mechanical devices to be shaken, and academically vibration means a phenomenon in which a balanced object is iteratively shaken. The vibration pattern of the object may be periodical movement like a pendulum or a non-periodical movement like an earthquake. In particular, when vibration occurs in the object, the object experiences displacement of mass and change in speed, and this means existence of acceleration. In other words, when vibration is applied to the object, a force, that is, a vibration force, is generated and the vibration force affects peripheral objects or supported portions.
In particular, a ship may use an object (hereinafter referred to as a vibration source) that generates vibration in the ship or an upper deck of the ship for realization of various engine facilities and various functional purposes. A pump is an example of a vibration source. Vibration generated by operation of the pump is directly transmitted to each parts of the ship body connected with the pump and thus noise is generated and the ship body is negatively affected. Due to such a reason, the vibration source such as a pump is generally provided with an attenuation means for reducing or absorbing vibration.
FIG. 1 shows a conventional vibration absorbing device. In FIG. 1, a pump P is provided as a vibration source in an upper portion of a ship body S. A plurality of vibration absorbing members 20 are disposed between the ship body S and the pump P. The vibration absorbing members 20 hold the pump P up from a bottom 10 of the ship body S, and function to prevent vibration or impact generated by the pump P from being transmitted to the ship body S by absorbing the vibration or impact.
However, the conventional vibration absorbing member 20 is mostly formed of a rubber material and thus vibration energy transmitted from the pump P is partially attenuated due to a characteristic of the material (e.g., viscoelasticity), and thus the vibration or impact cannot be actively absorbed.
Thus, development on a vibration absorbing device that can feed back vibration in real time and actively absorb the vibration rather than passively attenuating vibration applied from various vibration sources such as a pump is urgently required.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.